1. Field of the Invention
The present invention relates to an optical-semiconductor device including a light emitting device that can be used in display apparatus, illumination apparatus, backlight source for liquid crystal display and the like, and a light receiving device that can be used in video camera, digital still camera and the like, and a method for manufacturing the same. In particular, the present invention relates to a thin or compact optical-semiconductor device that has a high light-extraction efficiency and high contrast and can be manufactured with high yield, and a method for manufacturing the same.
2. Description of the Related Art
As electronics apparatuses become more compact and light-weight in recent years, efforts have also been made on optical-semiconductor devices such as light emitting device (light emitting diode, etc.) and light receiving device (CCD, photodiode, etc.) that are mounted on the electronics apparatuses, thereby developing compact ones. These optical-semiconductor devices comprise, for example, a double-side mounting printed circuit board with through holes that is made by forming metal circuit patterns on both sides of an insulating board. An optical-semiconductor elements such as light emitting element or light receiving element are mounted on the double-side mounting printed circuit board with through holes, and the optical-semiconductor elements are connected to the circuit pattern for electrical connection by using wires.
However, it is imperative for the optical-semiconductor device to use the double-side mounting printed circuit board with through holes. Since the double-side mounting printed circuit board with through holes has thickness of about 0.1 mm or more, it makes an obstacle to the effort of making a surface-mounted type optical-semiconductor device thinner.
For this reason, optical-semiconductor devices that do not use such a printed circuit board have been developed (refer to, for example, Japanese Unexamined Patent Publication (Kokai) No. 2005-79329).
The light emitting device disclosed in Japanese Unexamined Patent Publication (Kokai) No. 2005-79329 is made thinner than the conventional surface-mounted type light emitting device, by sealing electrodes that are formed from thin metal film by vapor deposition or the like on a substrate, together with light emitting element by means of a translucent resin.
However, since only the translucent resin is used, light-extraction efficiency is likely to decrease as light escapes from the light emitting element through the bottom surface. A structure of cone-shaped metal film for reflecting light has been proposed, although providing such a metal film makes it necessary to form pits in the surface of the substrate. Since the light emitting device is small in size, the pits must be very small and are difficult to form. In addition, because the structure has the pits, light emitting device is prone to breakage when the substrate is peeled off from the device, which leads to a lower yield of production and other problems. Also when the light emitting device is used in a display or the like, use of the translucent resin only tends to cause lower contrast.